Abstract

A formula is derived for the in‐plane effective mass in narrow quantum wells, taking into account the effects of energy band nonparabolicity. The variation of the mass with the width of the well is studied by using the formula for four systems of wells. The mass is nearly the same as the velocity effective mass of the bulk material of the well in GaAs/Ga0.7Al0.3As wells. It is about 8% larger in InAs/InP wells, but is significantly larger in very narrow wells of Ga0.47In0.53As/InP systems. In the case of InAs/Ga0.58Al0.42Sb wells, the in‐plane mass differs from the well mass by large amounts for all well widths of interest.